Rotor-stator systems are used in many fields of technology and generally comprise a rotating part (a rotor) moving relative to a static part (a stator) about an axis of rotation. Rotor-stator systems play an important role in rotational systems including wind tunnel model propellers/rotors, computer tomography imaging systems, helicopter drive systems, etc.
The rotating rotor part often may comprise electronics, such as sensors, for measuring the conditions of the rotational system such as pressure sensors, strain gauge sensors, temperature sensors, and vibration sensors. A data acquisition system on the rotor may collect the sensory data and contactless send the data to processing electronics located at the stator side. Typically, a data acquisition system on a rotor part is powered using a rotating contactless power transformer wherein energy transfer from the static primary coil to the rotating secondary coil takes place through a process known as mutual induction.
In certain applications such as wind tunnel model propeller/rotor technology, very high rotational speeds up to 10,000 RPM or even higher may be reached so the electronics, including the data acquisition and power transfer parts, on the rotor are exposed to very high centrifugal forces, elevated temperatures and/or vibrational forces. Furthermore, especially in a wind tunnel model testing environment, an ever-increasingly number of sensors need to be installed on the rotor part so that the data acquisition system should be able to process data rates of more than 100 Mbits/second and to send these data real-time to the electronics at the stator side. The increasing amount of sensor electronics on the rotor further poses a serious problem in terms of space and installation time.
Systems for contactless power and data transmission in rotational systems are known. For example, U.S. Pat. No. 7,197,113 describes a contactless power transfer system for use in a CT scanner. Various transformer designs are proposed in order to provide power transfer in such system. Under high centrifugal acceleration however, the rotating coil structure may change shape, which may lead to unstable electrical characteristics, failures and breakage of the mechanically sensitive brittle magnetic cores in the transformer part. Similarly, U.S. Pat. No. 7,717,619 describes a data transmission system for a rotational system wherein pickup antennas or pads are cantilevered at a distance from a stripline and/or microstrip transmitter. Such design may be prone to failure as high mechanical forces push and stretch the rotating part of the system. Furthermore, a cantilevered antenna lacks proper shielding and thus is more susceptible to noise. These contactless data and power transmission systems are not designed to provide a system that is compact, protected from external influences and simple to install.
From the above, it follows that known contactless rotating data acquisition and power transfer systems are not suitable for very high rotational speed applications. These known systems are dedicated systems which do not suggest contactless data and energy transfer systems that can withstand high rotational forces, that are easily installed and replaced and that allow efficient integration of the sensors in a limited space. Accordingly, there is a need for improved contactless power and/or data transmission systems that at least alleviates some of these problems.